System and method for treating obstructive sleep apnea

ABSTRACT

One aspect of the present disclosure relates to a system for treating obstructive sleep apnea in a subject. The system can include a power source and a neuromuscular stimulator in electrical communications with the power source. The neuromuscular stimulator can include a controller and at least one electrode. The controller can be configured to receive certain power and stimulation parameters associated with a therapy signal from the power source. The at least one electrode can be configured to deliver the therapy signal to a target tissue associated with control of a posterior base of the tongue of the subject.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/618,199, filed Jun. 9, 2017, which is a divisional of U.S. patentapplication Ser. No. 15/341,039, filed Nov. 2, 2016, now U.S. Pat. No.10,029,098, which is a divisional of U.S. patent application Ser. No.14/547,400, filed Nov. 19, 2014, now U.S. Pat. No. 9,757,560, whichclaims priority to U.S. Provisional Patent Application Ser. No.61/905,989, filed Nov. 19, 2013, and 61/994,149, filed May 16, 2014. Theentirety of each of the aforementioned applications is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to a system and method fortreating sleep disorders and, more particularly, to a system and methodfor treating obstructive sleep apnea.

BACKGROUND

Preterm Obstructive sleep apnea (OSA) is highly prevalent, affecting onein five adults in the United States. One in fifteen adults has moderateto severe OSA requiring treatment. Untreated OSA results in reducedquality of life measures and increased risk of disease includinghypertension, stroke, heart disease, etc. Continuous positive airwaypressure (CPAP) is a standard treatment for OSA. While CPAP isnon-invasive and highly effective, it is not well tolerated by patients.Patient compliance for CPAP is often reported to be between 40% and 60%.Surgical treatment options for OSA, such as anterior tongue musclerepositioning, orthognathic bimaxillary advancement,uvula-palatal-pharyngoplasty, and tracheostomy are available too.However, they tend to be highly invasive (result in structural changes),irreversible, and have poor and/or inconsistent efficacy. Even the moreeffective surgical procedures are undesirable because they usuallyrequire multiple invasive and irreversible operations, they may alter apatient's appearance (e.g., maxillo-mandibulary advancement), and/orthey may be socially stigmatic (e.g., tracheostomy) and extensivemorbidity.

SUMMARY

The present disclosure relates generally to a system and methods fortreating sleep disorders and, more particularly, to a system and methodsfor treating obstructive sleep apnea (OSA).

One aspect of the present disclosure relates to a system for treatingOSA in a subject. The system can comprise a power source and aneuromuscular stimulator in electrical communication with the powersource. The neuromuscular stimulator can include a controller and atleast one electrode. The controller can be configured to receive certainpower and stimulation parameters associated with a therapy signal fromthe power source. The at least one electrode can be configured todeliver the therapy signal to a target tissue associated with control ofa posterior base and lingual positioning of the tongue of the subject.

Another aspect of the present disclosure relates to a method fortreating OSA in a subject. One step of the method can include providinga system comprising a power source and a neuromuscular stimulator inelectrical communication with the power source. The neuromuscularstimulator can include a controller and at least one electrode. Thecontroller can be configured to receive certain power and stimulationparameters associated with a therapy signal from the power source. Next,the neuromuscular stimulator can be implanted in the subject so that theat least one electrode is in electrical communication with a targettissue associated with direct or indirect control of a posterior base ofthe tongue and posterior oropharyngeal airway of the subject. The powersource can then be activated so that the therapy signal is delivered tothe at least one electrode for a time and in an amount sufficient toopen the oropharyngeal airway to the laryngeal introitus.

Another aspect of the present disclosure relates to a method fortreating OSA in a subject. One step of the method can include providinga closed-loop system comprising a power source, a neuromuscularstimulator, and a sensing component. The neuromuscular stimulator can bein electrical communication with the power source. The neuromuscularstimulator can include a controller and at least one electrode. Thecontroller can be configured to receive certain power and stimulationparameters associated with a therapy signal from the power source. Thesensing component can be configured to detect at least one physiologicalparameter or a related symptom associated with OSA. Next, the system canbe implanted in the subject so that the at least one electrode and thesensing component are in electrical communication with first and secondtarget tissues, respectively, associated with direct or indirect controlof a posterior base of the tongue and posterior oropharyngeal airway ofthe subject. A sensor signal can then be generated by the sensingcomponent based on a detected at least one physiological parameter or arelated symptom associated with OSA. The controller can activate theneuromuscular stimulator to adjust application of the therapy signal tothe first target tissue in response to the sensor signal to treat theOSA.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomeapparent to those skilled in the art to which the present disclosurerelates upon reading the following description with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic illustration of a system for treating obstructivesleep apnea (OSA) constructed in accordance with one aspect of thepresent disclosure;

FIG. 2 is a schematic illustration showing a power source of the systemin FIG. 1 configured as a chin strap;

FIG. 3 is a schematic illustration of a closed-loop system for treatingOSA according to another aspect of the present disclosure;

FIG. 4 is a perspective view of a system for treating OSA configured asa chin implant;

FIG. 5 is a cross-sectional view taken along Line 4-4 of the chinimplant in FIG. 4;

FIG. 6A is a frontal view of a human skull and mandible with the chinimplant of FIG. 4 correctly positioned;

FIG. 6B is a profile view of the skull depicted in FIG. 6A;

FIG. 7 is a process flow diagram illustrating a method for treating OSAaccording to another aspect of the present disclosure;

FIG. 8 is a schematic illustration showing the neuromuscular stimulatorin FIG. 1 implanted in a subject;

FIG. 9 is a schematic illustration showing a magnified view of theneuromuscular stimulator in FIG. 8;

FIG. 10 is a schematic illustration showing the neuromuscular stimulatorin FIG. 9 implanted in the subject; and

FIG. 11 is a process flow diagram illustrating a method for treating OSAin a subject according to another aspect of the present disclosure.

DETAILED DESCRIPTION Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which the present disclosure pertains.

In the context of the present disclosure, the terms “modulate” or“modulating” can refer to causing a change in neuronal and/or muscleactivity, chemistry, and/or metabolism. The change can refer to anincrease, decrease, or even a change in a pattern of neuronal and/ormuscle activity. The terms may refer to either excitatory or inhibitorystimulation, or a combination thereof, and may be at least electrical,magnetic, optical or chemical, or a combination of two or more of these.

As used herein, the term “electrical communication” can refer to theability of an electric field generated by an electrode or electrodearray to be transferred, or to have a neuromodulatory effect, withinand/or on a target tissue, such as a muscle or nerve.

As used herein, the term “subject” can refer to any warm-bloodedorganism including, but not limited to, human beings, pigs, rats, mice,dogs, goats, sheep, horses, monkeys, apes, rabbits, cattle, etc.

As used herein, the terms “obstructive sleep apnea” or “OSA” can referto a breathing disorder that occurs primarily during sleep withconsequences that may persist throughout the waking hours in the form ofsleepiness. OSA can be characterized by periodic collapse of the upperairway during sleep with apneas, hypopneas, or a continuous or sustainedreduction in ventilation and excessive daytime sleepiness,neurocognitive defects and depression.

As used herein, the term “treating” can refer to therapeuticallyregulating, preventing, improving, alleviating the signs and symptomsof, and/or reducing the effects of a sleeping disorder, such as OSA andoropharyngeal airway obstruction. The term can also refer to chronic oracute treatment.

As used herein, the term “therapy signal” can refer to an electricaland/or chemical signal that is delivered to a target tissue and iscapable of modulating (e.g., electrically modulating) the target tissueand/or a bodily organ (e.g., a tongue) associated with the targettissue.

When an element or structure is referred to herein as being “on,”“engaged to,” “connected to,” “attached to”, or “coupled to” anotherelement or structure, it may be directly on, engaged, connected orcoupled to the other element or structure, or intervening elements orstructures may be present. In contrast, when an element is referred toas being “directly on,” “directly engaged to,” “directly connected to,”or “directly coupled to” another element or structure, there may be nointervening elements or structures present. Other words used to describethe relationship between elements should be interpreted in a likefashion (e.g., “between” versus “directly between,” “adjacent” versus“directly adjacent,” etc.).

Overview

The present disclosure relates generally to a system and method fortreating sleep disorders and, more particularly, to a system and methodfor treating OSA. As shown in FIG. 1, one aspect of the presentdisclosure can include a system 10 for treating a sleeping disorder,such as OSA. OSA affects almost every system in the body and, in someindividuals, can result in increased incidence of cardiovasculardisease. As discussed in more detail below, the present disclosureprovides a minimally invasive, implantable system 10 configured tomodulate one or more muscles of the anterior lingual musculature 12(FIG. 8) and thereby open airflow and prevent or mitigate obstructionduring sleep. Advantageously, the present disclosure helps to minimizethe deleterious effects of OSA on the day-to-day life of individualssuffering from OSA, as well as preventing or mitigating stress oncertain muscles that are being unnecessarily stimulated as a result ofOSA. Such advantages are realized, at least in part, because: (1) only asingle surgical site is required for implantation of the system 10; (2)the system can be configured for highly selective stimulation of one ormore muscles comprising the anterior lingual musculature; (3) dissectionof the hypoglossal nerve trunk is not required to practice the presentdisclosure; (4) implantation of the system does not produce any visiblescarring; and (5) once implanted, subjects cannot see, feel, or sensethe presence of the system.

System

In one aspect, the present disclosure can include a system 10 (FIG. 1)for treating OSA in a subject. The system 10 can comprise a power source14 in electrical communication with a neuromuscular stimulator 16. Thepower source 14 and the neuromuscular stimulator 16 can be in directand/or indirect electrical communication with one another. In someinstances, the power source 14 and the neuromuscular stimulator 16 canbe in direct electrical communication with one another via one or morewires (not shown). In other instances, the power source 14 and theneuromuscular stimulator 16 can be in indirect electrical communicationwith one another (e.g., via a wireless link). The system 10 can beportable and adapted to be borne by a subject suffering from OSA for adesired period of time. In some instances, the system 10 can be borne bya subject for an acute period of time (e.g., during an emergencysituation), for a semi-chronic period of time (e.g., less than about aweek to about 6 weeks), or for a chronic period of time (e.g., greaterthan about 6 weeks). For example, the neuromuscular stimulator 16 can betemporarily or permanently implanted within, on, or otherwise associatedwith a subject suffering from OSA.

In another aspect, the power source 14 can be configured to deliver atherapy signal having certain power and stimulation parameters to theneuromuscular stimulator 16. Examples of such power and stimulationparameters can include the pulse waveform, the signal pulse width, thesignal pulse frequency, the signal pulse phase, the signal pulsepolarity, the signal pulse amplitude, the signal pulse intensity, andthe signal pulse duration of the therapy signal. The power source 14 canbe capable of conveying a variety of currents and voltages to theneuromuscular stimulator 16. In some instances, the power source 14 cancommunicate stimulating energy, such as electrical current pulses to theneuromuscular stimulator. The power source 14 can optionally includecircuitry and/or other implantable components for outputting electricalpulses to the neuromuscular stimulator 16. Signals from the power source14 can additionally or optionally be communicative in nature, forexample, communicating stimulation program information, subjectinformation, and other types of information. In some instances, thepower source 14 is located external to the subject and in electricalcommunication with the neuromuscular stimulator 16 via inductivecoupling. For example, the power source 14 can be configured as part ofa wearable device, such as a chin strap 18 (FIG. 2), which may be wornat bedtime. In such instances, the power source 14 is not physically“wired” to the neuromuscular stimulator 16 (FIG. 1).

In another aspect, the neuromuscular stimulator 16 can include anyactive implantable medical device configured for implantation for arelatively short or long period of time. As shown in FIG. 1, theneuromuscular stimulator 16 can include a housing 20 connected to one ormore electrical leads 22 having at least one electrode 24 associatedtherewith. Various electrical components, such as a controller 26, canbe hermetically sealed and contained within the housing 20. As discussedin more detail below, all or only a portion of the neuromuscularstimulator 16 can be configured for implantation on or in the mandibleof a subject. For example, all or only a portion of the neuromuscularstimulator 16 can be configured for implantation on, in, or through amandible 28 (e.g., the mentum 29) (FIG. 8) of the subject.

The controller 26 (FIG. 1) can be configured to receive the power andstimulation parameters associated with a therapy signal from the powersource 14. In some instances, the controller 26 can include amicroprocessor (not shown), a hardwired circuit (not shown), or otherappropriate means for controlling various aspects of the system 10. Forexample, the controller 26 can operate the power source 14, conveytherapy signals to the at least one electrode 24, and/or receiveinformation from various sources, such as the at least one electrode ora sensor (not shown). The controller 26 can be configured to store astimulation program (or programs) and operate the power source 14according to the stimulation program(s). Stimulation programs caninclude predetermined, set programs (e.g., hardwired into thecontroller) and adaptive, dynamic programs (e.g., software that adaptsan artificial stimulation pattern according to various inputs). Thecontroller 26 can select between various programs and/or actively modifya stimulation program according to various inputs, such as informationreceived from a subject, information received from a sensor, informationreceived from the power source 14, information received from the atleast one electrode 24, and/or information received from a health careprovider.

In another aspect, the lead 22 of the neuromuscular stimulator 16 caninclude at least one electrode 24 that is in electrical communicationwith the controller 26. The at least one electrode 24 can be configuredto deliver a therapy signal to a target tissue associated with direct orindirect control of a posterior base of the tongue of a subject. Infurther describing representative electrodes 24, which are described inthe singular, it will be apparent that more than one electrode may beused as part of the system 10. Accordingly, the description of arepresentative electrode 24 suitable for use in the system 10 of thepresent disclosure is applicable to other electrodes that may beemployed.

The electrode 24 can include one or more of the following types and/orcategories of electrodes: epimysial electrodes; intramuscularelectrodes, such as Peterson electrodes; nerve cuff electrodes;self-contained electrodes; monopolar electrodes; bipolar electrodes;multi-contact electrodes; and/or other known electrode types/categoriesand combinations thereof. It will be appreciated that the electrode 24can include one or more associated flexible, extensible electrical leads22. The lead 22 and/or the electrode 24 can be highly flexible so as tonot hinder regular tongue movement. In some instances, all or only aportion of the lead 22 can include one or more deployable anchoringelements (not shown) (e.g., barbs, hooks, etc.). The anchoringelement(s) can be selectively retractable and extendable. The anchoringelement(s) facilitate secure placement of the lead 22 (and thus theelectrode 24) in or about a target tissue, such as a muscle, which isunder constant flexion and relaxation.

The electrode 24 can be controllable to provide therapy signals that maybe varied in voltage, frequency, pulse-width, current and/or intensity.For example, the electrode 24 can also provide both positive andnegative current flow from the electrode and/or be capable of stoppingcurrent flow from the electrode and/or changing the direction of currentflow from the electrode. In some instances, the electrode 24 has thecapacity for variable output, linear output and short pulse-width. Inother instances, the electrode 24 can comprise a coil configured todeliver magnetic stimulation. The electrode 24 may be mono-polar,bipolar or multi-polar. To minimize the risk of an immune responsetriggered by the subject against certain components of the neuromuscularstimulator 16, and also to minimize damage thereto (e.g., corrosion fromother biological fluids, etc.), the electrode 24 (and any wires andoptional housing materials) can be made of inert materials, such assilicon, metal, plastic and the like. In other instances, the electrode24 can be a multi-vector electrode capable of directing current todifferent muscles of anterior lingual musculature 12. In furtherinstances, the system 10 can include more than one electrode 24, such asan array of electrodes to stimulate a field of aborizing hypoglossalbranches associated with a particular target muscle (or group ofmuscles).

In another aspect, the system 10 can be configured as an open-loop orclosed-loop system. In an open-loop system, for example, a physician orthe subject may, at any time, manually or by the use of pumps, motorizedelements, etc., adjust treatment parameters of the system 10.Alternatively, in a closed-loop system (discussed below), treatmentparameters (e.g., electrical signals) may be automatically adjusted inresponse to a sensed physiological parameter or a related symptomindicative of the extent of OSA. In a closed-loop feedback system, asensor that senses a physiological parameter associated with OSA (e.g.,muscle or nerve electrical activity, tongue position, oropharyngealairfow, etc.) can be utilized. More detailed descriptions of sensorsthat may be employed in a closed-loop system, as well as other examplesof sensors and feedback control techniques that may be employed as partof the present disclosure are disclosed in U.S. Pat. No. 5,716,377.

Closed-Loop System

In another aspect, the present disclosure can include a closed-loopsystem 50 (FIG. 3) for treating OSA in a subject. The system 50 cancomprise a power source 14, a neuromuscular stimulator 16, and acontroller 26. The power source 14 and the neuromuscular stimulator 16can be in direct and/or indirect electrical communication with oneanother. In some instances, the power source 14 and the neuromuscularstimulator 16 can be in direct electrical communication with one anothervia one or more wires (not shown). In other instances, the power source14 and the neuromuscular stimulator 16 can be in indirect electricalcommunication with one another (e.g., via a wireless link). One or morecomponents of the system 50 can be implantable in a subject sufferingfrom OSA for a desired period of time (e.g., acute, semi-chronic,chronic). The system 50 can also be portable and adapted to be borne bya subject suffering from OSA for a desired period of time. In someinstances, the system 50 can be borne by a subject for an acute periodof time (e.g., during an emergency situation), for a semi-chronic periodof time (e.g., less than about a week to about 6 weeks), or for achronic period of time (e.g., greater than about 6 weeks). For example,the neuromuscular stimulator 16 can be temporarily or permanentlyimplanted within, on, or otherwise associated with a subject sufferingfrom OSA.

In another aspect, the power source 14 can be configured to deliver atherapy signal having certain power and stimulation parameters to theneuromuscular stimulator 16. Examples of such power and stimulationparameters can include the pulse waveform, the signal pulse width, thesignal pulse frequency, the signal pulse phase, the signal pulsepolarity, the signal pulse amplitude, the signal pulse intensity, andthe signal pulse duration of the therapy signal. The power source 14 canbe capable of conveying a variety of currents and voltages to theneuromuscular stimulator 16. In some instances, the power source 14 cancommunicate stimulating energy, such as electrical current pulses to theneuromuscular stimulator. The power source 14 can optionally includecircuitry and/or other implantable components for outputting electricalpulses to the neuromuscular stimulator 16. Signals from the power source14 can additionally or optionally be communicative in nature, forexample, communicating stimulation program information, subjectinformation, and other types of information. In some instances, thepower source 14 is located external to the subject and in electricalcommunication with the neuromuscular stimulator 16 via inductivecoupling. For example, the power source 14 can be configured as part ofa wearable device, such as a chin strap (not shown), which may be wornat bedtime. In such instances, the power source 14 is not physically“wired” to the neuromuscular stimulator 16.

In another aspect, the neuromuscular stimulator 16 can include anyactive implantable medical device configured for implantation for arelatively short or long period of time. As discussed in more detailbelow, all or only a portion of the neuromuscular stimulator 16 can beconfigured for implantation on or in the mandible of a subject. Forexample, all or only a portion of the neuromuscular stimulator 16 can beconfigured for implantation on, in, or through a mandible 28 (e.g., thementum 29) of the subject.

The controller 26 can be configured to receive the power and stimulationparameters associated with a therapy signal from the power source 14. Insome instances, the controller 26 can include a microprocessor (notshown), a hardwired circuit (not shown), or other appropriate means forcontrolling various aspects of the system 50. For example, thecontroller 26 can operate the power source 14, convey therapy signals toat least one electrode 24, and/or receive information from varioussources, such as the electrode or a sensing component 52. The controller26 can be configured to store a stimulation program (or programs) andoperate the power source 14 according to the stimulation program(s).Stimulation programs can include predetermined, set programs (e.g.,hardwired into the controller) and adaptive, dynamic programs (e.g.,software that adapts an artificial stimulation pattern according tovarious inputs). The controller 26 can select between various programsand/or actively modify a stimulation program according to variousinputs, such as information received from a subject, informationreceived from the sensing component 52, information received from thepower source 14, information received from the at least one electrode24, and/or information received from a health care provider.

In another aspect, the neuromuscular stimulator 16 can include one ormore leads 22 (FIG. 4), each of which has at least one electrode 24 inelectrical communication with the controller 26. The at least oneelectrode 24 can be configured to deliver a therapy signal to a targettissue associated with direct or indirect control of a posterior base ofthe tongue of a subject. In further describing representative electrodes24, which are described in the singular, it will be apparent that morethan one electrode may be used as part of the system 50. Accordingly,the description of a representative electrode 24 suitable for use in thesystem 50 of the present disclosure is applicable to other electrodesthat may be employed.

The electrode 24 can include one or more of the following types and/orcategories of electrodes: epimysial electrodes; intramuscularelectrodes, such as Peterson electrodes; nerve cuff electrodes;self-contained electrodes; monopolar electrodes; bipolar electrodes;multi-contact electrodes; and/or other known electrode types/categoriesand combinations thereof. It will be appreciated that the electrode 18can include one or more associated flexible, extensible electrical leads22. The lead 22 and/or the electrode 24 can be highly flexible so as tonot hinder regular tongue movement. In some instances, all or only aportion of the lead 22 can include one or more deployable anchoringelements (not shown) (e.g., barbs, hooks, etc.). The anchoringelement(s) can be selectively retractable and extendable. The anchoringelement(s) facilitate secure placement of the lead 22 (and thus theelectrode 24) in or about a target tissue, such as a muscle, which isunder constant flexion and relaxation.

The electrode 24 can be controllable to provide therapy signals that maybe varied in voltage, frequency, pulse-width, current and/or intensity.For example, the electrode 24 can also provide both positive andnegative current flow from the electrode and/or be capable of stoppingcurrent flow from the electrode and/or changing the direction of currentflow from the electrode. In some instances, the electrode 24 has thecapacity for variable output, linear output and short pulse-width. Inother instances, the electrode 24 can comprise a coil configured todeliver magnetic stimulation. The electrode 24 may be mono-polar,bipolar or multi-polar. To minimize the risk of an immune responsetriggered by the subject against certain components of the neuromuscularstimulator 16, and also to minimize damage thereto (e.g., corrosion fromother biological fluids, etc.), the electrode 24 (and any wires andoptional housing materials) can be made of inert materials, such assilicon, metal, plastic and the like. In other instances, the electrode24 can be a multi-vector electrode capable of directing current todifferent muscles of anterior lingual musculature. In further instances,the system 50 can include more than one electrode 24, such as an arrayof electrodes to stimulate a field of aborizing hypoglossal branchesassociated with a particular target muscle (or group of muscles).

In another aspect, the system 50 also includes one or more sensingcomponents 52 configured to detect at least one physiological parameteror a related symptom of OSA. The presence of the sensing component 52enables closed-loop operation of the system 50 to treat OSA, meaningthat treatment parameters (e.g., therapy signals) may be automaticallyadjusted in response to the sensed or detected physiological parameteror a related symptom of OSA. In some instances, the sensing component 52and the electrode 24 can be the same structure or element.Advantageously, use of a single structure or element as the sensingcomponent 52 and the electrode 24 reduces the invasive nature of thesurgical procedure associated with implanting the system 50, while alsoreducing the number of foreign bodies introduced into a subject.

The sensing component 52 can be in direct and/or indirect electricalcommunication with the controller 26 and/or the power source 14 (e.g.,via one or more leads 22 or a wireless link). In one example, thesensing component 52 can comprise a sensor (e.g., an electrode 24 asdescribed above) that senses a physiological parameter or relatedsymptom associated with OSA (e.g., muscle or nerve electrical activity,tongue position, oropharyngeal airflow, etc.). Examples of sensors thatmay be employed in a closed-loop system 50, as well as other examples ofsensors and feedback control techniques that may be employed as part ofthe present disclosure are disclosed in U.S. Pat. No. 5,716,377.

The system 50 can be configured for highly selective stimulation andmodulation of the anterior lingual musculature. In some instances, thesystem 50 can comprise multiple leads 22, each of which includes atleast one electrode 24 and at least one sensing component 52. Forexample, the system 50 can have an “octopus-like” configuration wherebythe tentacles correspond to the multiple leads 22 and the bodycorresponds to the neuromuscular stimulator 16. A distal end of each ofthe leads 22 can be configured for embedding into a pre-determinedportion of a muscle comprising the anterior lingual musculature. Themuscle(s) in which the distal ends of the leads 22 is/are embedded canbe the same or different. Thus, in some instances, the distal ends ofthe leads 22 can be embedded in a single muscle but at different spatiallocations. In such instances, the system 50 can be operated to activate(stimulate) a first portion of the muscle associated with a first lead(not shown), while simultaneously or sequentially inhibiting musclefunction in a second different portion of the muscle associated with asecond lead (not shown). Advantageously, a system 50 having amultiple-lead configuration provides highly selective control overtargeted muscles of the anterior lingual musculature and, thus, theability to therapeutically modulate the laryngeal introitus.

One example of a system 50 for treating OSA is illustrated in FIGS.4-6B. The system 50 can comprise a chin implant 54 for a human mandible28 (FIGS. 6A-B). The chin implant 54 (FIG. 4) has a generallycrescent-shaped configuration and, when implanted, gives the appearanceof a natural chin contour. All or only a portion of the chin implant 54can be made of one or more materials that is/are biologically inert andnon-reactive to avoid infection in a subject's body (e.g., siliconeand/or or plastic). By virtue of its construction, the chin implant 54can be pliant, flexible and compressible.

As shown in FIGS. 4-5, the chin implant 54 can comprise an implant body56, a controller 26, at least one electrode 24, a sensing component 52,and a power source 14. The implant body 56 can have a front face 58 anda back face 60. The back face 60 can have a surface 62 for placementadjacent the mental protuberance 64 of the mandible 28 (FIG. 6A). Thefront face 58 can have a curved projection surface 66 for protrudingfrom the chin to create a natural chin profile after implantation (FIG.6B). Each of the controller 26, the at least one electrode 24, thesensing component 52, and the power source 14 can be directly orindirectly associated with the implant body 56. As shown in FIG. 4, forexample, the controller 26 and the power source 14 can be housed withina portion of the implant body 56, while the at least one electrode 24and the sensing component 52 are located external to the implant bodyand directly connected to the controller (e.g., by leads 22). Althoughthe power source 14 is shown as being disposed within the implant body56, it will be appreciated that the power source may also be locatedexternal to the implant body (e.g., via a wireless link).

Methods

Another aspect of the present disclosure can include a method 30 (FIG.7) for treating OSA in a subject. The method 30 can generally includethe steps of providing a system 10 (Step 32), implanting a neuromuscularstimulator 16 of the system into a subject suffering from OSA (Step 34),and activating the system to treat the OSA (Step 36). The system 10provided at Step 32 can be identically or similarly constructed as thesystem shown in FIG. 1 and described above. For the purpose ofillustration only, the method 30 will be described below using thesystem 10 shown in FIG. 1.

At Step 34, the neuromuscular stimulator 16 can be implanted in thesubject. In some instances, a trans-mandibular surgical approach can beused to implant the neuromuscular stimulator 16. A variety oftrans-mandibular surgical approach options may be used, such as asubmental approach or an intraoral bucca-gingival sulcus approach.Generally speaking, a submental approach allows for other adjunctiveprocedures including, but not limited to, cervical liposuction (e.g.,for effacement of platysmal banding), elevation of hyoid positioning,and mandibular distal bone advancement for aesthetic purposes and/orfunctionally repositioning the anterior lingual musculature 12. Unlikethe submental approach, an intraoral approach does not produce a facialscar. A trans-mandibular surgical approach can be performed under localanesthetic or in an outpatient setting; however, it will be appreciatedthat general anesthetic may alternatively be used as patients may bemore comfortable and the patient's airway is better protected.

Whether a submental or intraoral bucca-gingival sulcus approach is used,the dissection can be carried out to the level of the periosteumoverlying the mentum 29 of the mandible 28 (FIG. 8). Surgical awarenessis highlighted at this time in an effort to preserve and not traumatizethe mental nerves (not shown). The mental nerves exit at themid-vertical level of the mandible 28, between the region of the firstand second pre-molars bilaterally. Like many surgeries in the head andneck, preservation of a nerve (or nerves) along with strict attention tohemostasis are key features of a successful operation. In making thegingivo-labial sulcus incision, for example, it can be important toleave an adequate cuff of mucosa along with a sufficient portion of thementalis muscle (not shown) for later resuspension. Doing so can avoidlower-lip ptosis.

FIGS. 8-10 illustrate a submental approach for implanting theneuromuscular stimulator 16 in a subject. First, an external submentalcrease incision (not shown) can be made. A subperiosteal dissection canthen be made to elevate the periosteum and protect the mental nerves. Atthis point, a surgical mark can be made at the midline of the bonymentum 29. One or more drill holes (not shown) can be made above theinferior edge of the mentum 29, and on either side of the midline. Forexample, multiple drill holes can be made about 1 cm above the inferioredge of the mentum 29, and about 1.5 cm on either side of the midline.The diameter of each drill hole should be sufficient to pass the lead(s)22 of the neuromuscular stimulator 16 through both cortices of themandible 28 into electrical communication with one or more of thesublingual muscles that control the anterior positioning of the tonguebase when contraction occurs.

In another example, an intraoral bucca-gingival sulcus approach canalternatively be used to implant the neuromuscular stimulator 16.Subperiosteal dissection can be carried out laterally to identify themental nerves. The foramina (not shown) of the mental nerves aregenerally found between the first and second premolar teeth at the levelof the origin of the mentalis muscle, or 2-4 mm below the level of thebicuspid premolar teeth apices. The foramina are situated deep to themidportion of the depressor anguli oris. Dissection can occurinferolaterally to allow for a longer osteotomy and thereby preventunsightly mandibular notching. During dissection, the periosteum at theinferior rim of the mentum 29 can be left intact. Next, the skeletalmidline can be aligned with the overlying soft tissue corollary. Asagittal saw with a 30-degree bend can then be used to facilitate aneven cut while minimizing soft tissue trauma. Lateral cuts can be madeabout 4-5 mm below the foramina to compensate for the path of theinferior alveolar nerve.

In another variation of the method 30, the neuromuscular stimulator 16can be configured to also serve as a chin implant. This may be desirablein instances where a subject desires an aesthetic change to theiranterior mandibular profile. Alternatively, if a subject does not desirea change in their anterior mandibular profile, a relatively small orlow-profile neuromuscular stimulator 16 that does not cause any profilechanges can be used. For example, a neuromuscular stimulator 16 can besized and dimensioned for placement within a drilled sulcus such thatattachment of the neuromuscular stimulator therein does not interferewith the anterior mandibular profile of the subject.

Regardless of the trans-mandibular surgical approach used, theneuromuscular stimulator 16 can be implanted so that the electrode 24 isin electrical communication with a target tissue associated with controlof a posterior base of the tongue of the subject (e.g., the electrodecan be placed directly on and/or within the target tissue). In someinstances, the electrode 24 can be placed into electrical communicationwith one or more muscles of the anterior lingual musculature 12. Inother instances, two or more electrodes 24 can be placed bilaterallyinto electrical communication with one or more muscles of the anteriorlingual musculature 12. In one example, the electrode 24 can be placedinto electrical communication with a genioglossus muscle (not shown). Inanother example, the electrode 24 can be placed into electricalcommunication with an anterior belly digastric muscle 38 (FIG. 9). Inanother example, the electrode 24 can be placed into electricalcommunication with a hyoglossus muscle (not shown). In another example,the electrode 24 can be placed into electrical communication with amylohyoid muscle (not shown).

Alternatively or additionally, the electrode 24 can be placed intoelectrical communication with a nerve (or nerves) that innervates one ormuscles associated with control of a posterior base of the tongue of thesubject, such as the hypoglossal nerve 40 and/or its distal arborizingbranches at or near its neuromuscular junction. In some instances, theelectrode 24 can be implanted directly in or on the target tissue. Inother instances, the electrode can be implanted so that the electrode 24is not in direct physical contact with the target tissue, but located insufficient proximity to the target tissue such that delivery of atherapy signal to the electrode can modulate target tissue activity.

Proper positioning of the lead 22 can be confirmed by delivering testsignals to the electrode 24 and then noting if the test signals resultin anterior displacement of the posterior base of the tongue. Once thelead 22 is properly positioned, the housing 20 can be securely affixedto the subject. For example, the housing 20 can be securely affixed(e.g., with bone screws) into the external cortex of the mandible 28, orsimply placed in a tight surgical subperiosteal pocket. Once theneuromuscular stimulator 16 is secured to the subject, the soft tissuecan be closed in layers while paying special attention to thereattachment of the mentalis muscle to avoid ptotic lower lip. The softtissue can then be re-draped with tape and the procedure completed (FIG.10). Overall, the surgical implant procedure can take about 15 minutesto complete.

At Step 34, the power source 14 can be associated with the subject (ifit has not been done so already) so that the power source is inelectrical communication with the neuromuscular stimulator 16. As shownin FIG. 2 and discussed above, for example, the power source 14 can beconfigured as a chin strap 18 and placed around the head of the subject.

With the neuromuscular stimulator 16 implanted in the subject, the powersource 14 can be activated at Step 36. Activation of the power source 14causes one or more therapy signals, having desired power and stimulationparameters, to be delivered to the neuromuscular stimulator 16. In someinstances, the therapy signal(s) (e.g., an electrical signal) may beconstant, varying and/or modulated with respect to the current, voltage,pulse-width, cycle, frequency, amplitude, and so forth. For example, acurrent may range from about 0.001 to about 1000 microampere (mA) and,more specifically, from about 0.1 to about 100 mA. Similarly, thevoltage may range from about 0.1 millivolt to about 25 volts, or about0.5 to about 4000 Hz, with a pulse-width of about 10 to about 1000microseconds. The type of stimulation may vary and involve differentwaveforms known to the skilled artisan.

Depending upon the desired treatment regimen, the therapy signal(s)is/are relayed to the electrode 24. The therapy signal(s) can be relayedto the electrode 24 for a time and in an amount sufficient to displacethe posterior base of the tongue in an anterior direction, which opensthe oropharyngeal airway to the laryngeal introitus. Delivery of thetherapy signal(s) to the target tissue can be done, for example, whilethe subject is sleeping. In patients with OSA, the posterior base of thetongue can fall backwards and obstruct breathing, especially whenindividuals lay flat on their backs. Therapy signal(s) from theneuromuscular stimulator 16 can be delivered to the target tissue on acontinuous, periodic, or an as-needed basis to displace the posteriorbase of the tongue in an anterior direction (and/or change the surfacemorphology of the posterior tongue base to allow and increaseoropharyngeal airway volume) while the subject is sleeping. Thisprevents obstruction of the airway during sleep by ensuring that airflowthrough the airway of the subject is properly maintained. Additionallyor optionally, the therapy signal(s) can be relayed to the electrode 24to achieve selective muscle activation; that is, targeted activation ofless than all of the muscles comprising the anterior lingual musculature12. Advantageously, selective stimulation of the anterior lingualmusculature 12 can prevent or mitigate dysarthria.

Another aspect of the present disclosure can include a method 70 (FIG.11) for treating OSA in a subject. The method 70 can generally includethe steps of: providing a closed-loop system 50 (Step 72); implantingthe system into a subject suffering from OSA (Step 74); generating asensor signal based on a detected at least one physiological parameteror related symptom associated with OSA (Step 76); and delivering atherapy signal, by the system, to a target tissue to treat the OSA (Step78). Steps 76-78 can be repeated for a desired period of time to treatthe OSA (Step 80). The closed-loop system 50 provided at Step 72 can beidentically or similarly constructed as the system shown in FIG. 3 anddescribed above. For example, the system 50 shown in FIG. 3 can beconfigured to include multiple electrodes 24 and sensing components 52,which may limit total extrinsic and intrinsic tongue contraction andassist in anterior-superior elevation of the suprahyoid muscles (andthus the hyoid bone) to open the laryngeal introitus.

At Step 74, the system 50 can be implanted in the subject. In someinstances, a trans-mandibular surgical approach can be used to implantthe system 50. A variety of trans-mandibular surgical approach optionsmay be used, such as a submental approach or an intraoral bucca-gingivalsulcus approach. Generally speaking, a submental approach allows forother adjunctive procedures including, but not limited to, cervicalliposuction (e.g., for effacement of platysmal banding), elevation ofhyoid positioning, and mandibular distal bone advancement for aestheticpurposes and/or functionally repositioning the anterior lingualmusculature. Unlike the submental approach, an intraoral approach doesnot produce a facial scar. A trans-mandibular surgical approach can beperformed under local anesthetic or in an outpatient setting; however,it will be appreciated that general anesthetic may alternatively be usedas patients may be more comfortable and the patient's airway is betterprotected.

Whether a submental or intraoral bucca-gingival sulcus approach is used,the dissection can be carried out to the level of the periosteumoverlying the mentum of the mandible 28. Surgical awareness ishighlighted at this time in an effort to preserve and not traumatize themental nerves (not shown). The mental nerves exit at the mid-verticallevel of the mandible, between the region of the first and secondpre-molars bilaterally. Like many surgeries in the head and neck,preservation of a nerve (or nerves) along with strict attention tohemostasis are key features of a successful operation. In making thegingivo-labial sulcus incision, for example, it can be important toleave an adequate cuff of mucosa along with a sufficient portion of thementalis muscle (not shown) for later resuspension. Doing so can avoidlower-lip ptosis.

In one example, a submental approach can be used to implant the system50 in a subject suffering from OSA. First, an external submental creaseincision (not shown) can be made. A subperiosteal dissection can then bemade to elevate the periosteum and protect the mental nerves. At thispoint, a surgical mark can be made at the midline of the bony mentum.One or more drill holes (not shown) can be made above the inferior edgeof the mentum, and on either side of the midline. For example, multipledrill holes can be made about 1 cm above the inferior edge of thementum, and about 1.5 cm on either side of the midline. The diameter ofeach drill hole should be sufficient to pass the leads 22 associatedwith the at least one electrode 24 and the sensing component 52 of thesystem 50 through both cortices of the mandible 28 into electricalcommunication with first and second target tissues, respectively.

In another example, an intraoral bucca-gingival sulcus approach canalternatively be used to implant the system 50. Subperiosteal dissectioncan be carried out laterally to identify the mental nerves. The foramina(not shown) of the mental nerves are generally found between the firstand second premolar teeth at the level of the origin of the mentalismuscle, or 2-4 mm below the level of the bicuspid premolar teeth apices.The foramina are situated deep to the midportion of the depressor angulioris. Dissection can occur inferolaterally to allow for a longerosteotomy and thereby prevent unsightly mandibular notching. Duringdissection, the periosteum at the inferior rim of the mentum can be leftintact. Next, the skeletal midline can be aligned with the overlyingsoft tissue corollary. A sagittal saw with a 30-degree bend can then beused to facilitate an even cut while minimizing soft tissue trauma.Lateral cuts can be made about 4-5 mm below the foramina to compensatefor the path of the inferior alveolar nerve.

The foregoing surgical approaches can include implantation of a chinimplant 54 (such as the one described above) in instances where asubject desires an aesthetic change to their anterior mandibularprofile. Alternatively, if a subject does not desire a change in theiranterior mandibular profile, a relatively small or low-profileneuromuscular stimulator 16 that does not cause any profile changes canbe used. For example, a neuromuscular stimulator 16 can be sized anddimensioned for placement within a drilled sulcus such that attachmentof the neuromuscular stimulator therein does not interfere with theanterior mandibular profile of the subject.

Regardless of the trans-mandibular surgical approach used, the system 50can be implanted so that the electrode 24 and the sensing component 52are in electrical communication with first and second target tissues,respectively (e.g., the electrodes can be placed directly on and/orwithin the first and second target tissue). The first and second targettissues can be the same or different. In some instances, the electrode24 can be placed into electrical communication with a first targettissue comprising one or more muscles of the anterior lingualmusculature 12 (e.g., one or a combination of suprahyoid muscles). Inone example, the electrode 24 and/or the sensing component 52 can beplaced into electrical communication with a genioglossus muscle (notshown). In another example, the electrode 24 and/or the sensingcomponent 52 can be placed into electrical communication with ananterior belly digastric muscle (not shown). In another example, theelectrode 24 and/or the sensing component 52 can be placed intoelectrical communication with a hyoglossus muscle (not shown). Inanother example, the electrode 24 and/or the sensing component 52 can beplaced into electrical communication with a mylohyoid muscle (notshown).

Proper positioning of the electrode 24 can be confirmed by deliveringtest signals to the electrode and then noting if the test signals resultin anterior displacement of the posterior base of the tongue. Once theelectrode 24 is properly positioned, the remainder of the system 50 canbe securely affixed to the subject. For example, the implant body 56 ofa chin implant 54 can be securely affixed (e.g., with bone screws) intothe external cortex of the mandible 28. Once the system 50 is securelyimplanted in the subject, the soft tissue can be closed in layers whilepaying special attention to the reattachment of the mentalis muscle toavoid ptotic lower lip. The soft tissue can then be re-draped with tapeand the procedure completed. Overall, the surgical implant procedure cantake about 15 minutes to complete.

If it has not been done so already, the power source 14 can beassociated with the subject so that the power source is in electricalcommunication with the neuromuscular stimulator 16. With the system 50implanted in the subject, the power source 14 can then be activated.Activation of the power source 14 enables the sensing component 52 todetect at least one physiological parameter or a related symptomassociated with OSA. Activation of the power source 14 also permits oneor more therapy signals having desired power and stimulation parametersto be delivered to the electrode 24. In some instances, the therapysignal(s) (e.g., an electrical signal) may be constant, varying and/ormodulated with respect to the current, voltage, pulse-width, cycle,frequency, amplitude, and so forth. For example, a current may rangefrom about 0.001 to about 1000 microampere (mA) and, more specifically,from about 0.1 to about 100 mA. Similarly, the voltage may range fromabout 0.1 millivolt to about 25 volts, or about 0.5 to about 4000 Hz,with a pulse-width of about 10 to about 1000 microseconds. The type ofstimulation may vary and involve different waveforms known to theskilled artisan.

At Step 76, a sensor signal can be generated by the sensing component 52in response to at least one physiological parameter or a related symptomassociated with OSA detected by the sensing component. Where the sensingcomponent 52 is an EMG electrode, for example, the activity of one ormore muscles of the anterior lingual musculature (e.g., a genioglossusmuscle or a suprahyoid muscle) can be detected. A detected decrease inmuscle activity (relative to a control or baseline level) may cause thesensing component 52 to generate a corresponding sensor signal, which isthen relayed to the controller 26 and/or the power source 14.

In response to the generated sensor signal, the system 50 can cause atherapy signal (or signals) to be delivered to the electrode 24 (Step78). The controller 26 can then control operation of the neuromuscularstimulator to adjust application of the therapy signal(s) to the firsttarget tissue in response to the sensor signal. For example, the therapysignal(s) can be relayed to the electrode 24 for a time and in an amountsufficient to displace the posterior base of the tongue in an anteriordirection, which opens the oropharyngeal airway to the laryngealintroitus. Delivery of the therapy signal(s) to the target tissue can bedone, for example, while the subject is sleeping. In patients with OSA,the posterior base of the tongue can fall backwards and obstructbreathing, especially when individuals lay flat on their backs. Therapysignal(s) from the neuromuscular stimulator 16 can be delivered to thefirst target tissue on a continuous, periodic, or an as-needed basis todisplace the posterior base of the tongue in an anterior direction(and/or change the surface morphology of the posterior tongue base toallow and increase oropharyngeal airway volume) while the subject issleeping. This prevents obstruction of the airway during sleep byensuring that airflow through the airway of the subject is properlymaintained. Additionally or optionally, the therapy signal(s) can berelayed to the electrode 24 to achieve selective muscle activation; thatis, targeted activation of less than all of the muscles comprising theanterior lingual musculature. Advantageously, selective stimulation ofthe anterior lingual musculature can prevent or mitigate dysarthria. Itwill be appreciated that although the method 70 is described in terms ofunilateral stimulation, the method can also be performed using bilateralstimulation (e.g., stimulating two muscles simultaneously or insequence).

As shown in FIG. 11, Steps 76-78 can be repeated for a period of time totreat the OSA. Advantageously, the method 70 provides a minimallyinvasive, automatic, and aesthetically acceptable treatment modality forOSA that is continually titrated to optimize its efficacy based oncontinuous physiological feedback, thereby enabling a high degree ofpatient-specific customization.

It will be appreciated that the present disclosure may also be anadjunct to other mechanical orthognathic maneuvers to sections of themandible that have tongue muscle attachments to them.

From the above description of the present disclosure, those skilled inthe art will perceive improvements, changes and modifications. Forexample, it will be appreciated that a subject may be placed in a sleeplab after surgery so that particular settings (e.g., stimulationparameters) of the system 10 and 50 can be optimized based on the needsof the subject. Additionally, it will be appreciated that, dependingupon the static placement of the sublingual muscles, a preoperativedecision can be made (e.g., based on soft and hard tissuecephalometrics) to reposition the anterior mentum and lingual muscleattachments to statically permit further advancement of the tongue basein concert with electrical stimulation of the sublingual muscles. Suchimprovements, changes, and modifications are within the skill of thosein the art and are intended to be covered by the appended claims. Allpatents, patent applications, and publication cited herein areincorporated by reference in their entirety.

The following is claimed:
 1. A system for improving disordered breathingthat occurs during sleep in a subject, the system comprising: astimulator comprising an array of electrodes configured to stimulatedistal arborizing branches of a hypoglossal nerve of the subject; apower source external to the stimulator; and a controller programmed todeliver a therapy signal to the array to stimulate the distal arborizingbranches of the hypoglossal nerve to improve the subject's disorderedbreathing that occurs during sleep.
 2. The system of claim 1, whereinthe controller is configured to store one or more stimulation programs.3. The system of claim 1, wherein the controller is programmed with apredetermined program.
 4. The system of claim 1, wherein the controlleris programmed with an adaptive program.
 5. The system of claim 1,wherein the controller is programmed with a predetermined program and anadaptive program.
 6. The system of claim 1, further comprising: anelectromyogram (EMG) electrode configured to detect muscle activity of amuscle that controls tongue movement.
 7. The system of claim 6, whereinthe stimulator comprises a lead and the array of electrodes and the EMGelectrode are disposed on the lead.
 8. The system of claim 1, whereinthe stimulator further includes: a housing within which the controlleris contained; and an electrical lead connected to the housing.
 9. Thesystem of claim 1, wherein the controller is configured to selectbetween stimulation programs, modify a stimulation program according toinput information, or combinations thereof.
 10. The system of claim 9,wherein the input information comprises information received from thesubject, information received from a sensor, information received fromthe power source, information received from at least one electrode ofthe electrode array, information received from a health care provider,or combinations thereof.
 11. The system of claim 1, wherein thedisordered breathing that occurs during sleep is obstructive sleep apnea(OSA).
 12. A method of improving disordered breathing that occurs duringsleep comprising: obtaining the stimulator of claim 1; delivering atherapy signal to the array of the stimulator to stimulate the distalarborizing branches of the hypoglossal nerve to improve the subject'sdisordered breathing that occurs during sleep.
 13. The method of claim12, further comprising: detecting an electromyogram (EMG) signal fromone or more muscles of the anterior lingual musculature; and adjustingapplication of the therapy signal(s) in response to the detected EMGsignal to improve the subject's improved disordered breathing thatoccurs during sleep.
 14. The method of claim 12, wherein the disorderedbreathing that occurs during sleep is OSA.